The present invention is a fan blade assembly characterized by strong, lightweight blades with contoured surfaces having airfoil characteristics which provide an optimal compromise to effectively circulate air in both a clockwise and a counterclockwise direction at relatively low rotational velocities. The fan blade assembly can include a lighting system having an illuminant housed within the fan blade. The fan blade assembly can be used singularly with a fan drive unit for a ceiling fan, or alternately, the assembly can be used in combination with a conventional ceiling fan and its existing fan blades.
Ceiling fans are used to circulate ambient air in a room or area. They are particularly useful in assisting heating and cooling systems. By increasing the air circulation, a ceiling fan can lower the amount of electrical power required to run heating and cooling systems.
The rotational speed, pitch, and diameter of the fan blades are the three major factors for consideration in moving air. Larger diameter blades which can move more air at a lower velocity are the most desirable for comfort and efficiency. Conventional ceiling fan blades have been limited to about five feet in diameter and therefore, must rotate at speeds up to 300 RPM (revolutions per minute) in order to move adequate amounts of air. The higher fan speeds can create uncomfortable drafts, as well as undesirable noise. If conventional blades are simply made larger, the weight of the blades proportionally increases and can reduce the efficiency of the motor. However, by increasing the diameter of the blades by 50%, the amount of air moved at the same rotational speed is more than doubled. Therefore, to move the same amount of air the fan blade speed could be cut by more than one half.
Conventional ceiling fan blades are generally planar with a two dimensional form. They are typically rotated in two directions, pushing the air downward for cooling circulation and upward for heating circulation. The two dimensional blades do not optimize air flow for bi-directional rotation which generally requires the more effective airflow when pushing downward during circulation for cooling, as opposed to when pushing upwardly to gently dissipate the hot air layering for heating circulation.
The present invention provides a fan assembly with fan blades that have a higher strength to weight ratio than conventional fan blades which enables the blade diameter to be larger than the conventional five feet, while maintaining the strength, weight, and integrity of the blade. With a larger diameter, the fan blade assembly of the present invention can move the same volume of air at a lower speed, that a conventional blade will move at a higher speed. Therefore, due to the efficiency of using a lower fan speed, the fan blade assembly of the present invention provides adequate air circulation at a reduced power requirement.
In addition, the shape and contour of the blades of the present invention can more effectively optimize circulation of the ambient air at lower velocities in both a clockwise and counterclockwise direction, wherein the downward thrust of circulating air is greater than the upward pulling. By using the present fan blade assembly on a ceiling fan, power consumption is minimized, the operating noise level is reduced and the air is circulated at an optimum speed in both an upward and downward direction for the user's comfort.